Field of the Disclosure
The present subject matter relates to assembly of components presented on separate moving webs and the resulting assemblies. This is suitable for making radio frequency identification (“RFID”) devices, more particularly for assembling RFID inlays and the inlays thus assembled.
Description of Related Art
RFID tags and labels (collectively referred to herein as “devices”) are widely used to associate an object with an identification code. RFID devices generally have a combination of antennae and analog and/or digital electronics, which may include, for example, communications electronics, data memory, and control logic. For example, RFID tags are used in conjunction with retail security systems, security locks in cars, for access control to buildings, and for tracking inventory and parcels. Some examples of RFID tags and labels appear in U.S. Pat. Nos. 6,107,920; 6,206,292; and 6,262,692, all of which are hereby incorporated herein by reference in their entireties.
Automatic identification of products has become commonplace. For example, the ubiquitous technology used for automatic identification products is RFID. RFID uses labels or “tags” that include electronic components that respond to radio frequency (“RC”) commands and signals to provide identification of each tag wirelessly. Generally, RFID tags and labels comprise an integrated circuit (“IC”, or chip) attached to an antenna that responds to a reader using radio waves to store and access the information in the chip. Specifically, RFID tags and labels have a combination of antennas and analog and/or digital electronics, which often includes communications electronics, data memory, and control logic.
One of the obstacles to more widespread adoption of RFID technology is that the cost of RFID tags and difficulties for optimization of economical manufacturing of RFID tags. Increased demand for RFID tags has manufacturers seeking cost reduction and manufacturing simplification. Also of importance is reducing the size of the electronics to: (1) increase the yield of the number of chips (dies) that may be produced from a semiconductor wafer, (2) reduce the potential for damage by providing smaller final devices, and (3) increase flexibility in deployment since reducing the amount of space needed to provide a given functionality may be used to provide more capability.
Assembly difficulties tend to increase as RFID chips and their components become smaller. For example, to interconnect the relatively small contact pads on the chips with the antennas, intermediate structures variously referred to as “straps,” “interposers,” and “carriers” are sometimes used to facilitate inlay manufacture. Interposers include conductive leads or pads that are electrically coupled to the contact pads of the chips for coupling to the antennas. These leads provide a larger effective electrical contact area between the chips and the antenna than do the contact pads of the chip alone. Otherwise, an antenna and a chip would have to be more precisely aligned with each other for direct placement of the chip on the antenna without the use of such strap. The larger contact area provided by the strap reduces the accuracy required for placement of the chips during manufacture while still providing effective electrical connection between the chip and the antenna. However, the accurate placement and mounting of the dies on straps and interposers still provide serious obstacles for high speed manufacturing of RFID tags and labels.
Typically the various elements that are assembled to form a complete RFID device are provided arranged on linear arrays such as on a substrate, tape or web. They then are assembled together (for example by application of heat, pressure, adhesives, solder, mechanical fasteners, any combination of the foregoing, etc.). For purposes of increasing efficiency, the pitch of these articles (i.e. spacing between them) on the substrate is typically as close as practicable. In the case of antennas and straps, however, because of their different physical size and their respective manufacturing processes as well as subsequent assembly steps for the final product, the pitch of the arrays of the antennas and of the straps on their respective substrates often is different. Thus, properly registering (i.e. matching) a strap array with an antenna array is rather difficult. Current solutions to this problem include cutting each individual strap and accelerating it to meet the respective antenna at the point of assembly, unwinding the two webs at different speeds, or displacing material web length of one web in order to draw adjacent components closer and thus reduce pitch.